In short: A consortium led by the Compound Semiconductor Applications Catapult, Lime Microsystems, and Arqit has built a compact base station prototype that integrates quantum-grade encryption with energy-efficient GaN power amplifiers, addressing two of the biggest concerns about disaggregated 5G networks -- security and power consumption -- in a single piece of hardware.
Key Takeaways
- Quantum encryption at the radio edge — Arqit's QuantumCloud key agreement platform is integrated directly into the base station, securing the air interface against both classical and future quantum computing attacks
- GaN amplifiers cut power draw — custom gallium nitride power amplifiers deliver the required RF performance at significantly lower energy consumption than conventional silicon alternatives
- One prototype, two problems solved — the "base-station-in-a-box" demonstrates that disaggregated networks can be both more secure and less power-hungry than the integrated equipment they replace
In a nutshell
Two Persistent Objections
Open and disaggregated 5G networks have answered many early objections — interoperability, performance, operator confidence — but two concerns remain stubbornly persistent, and they are the ones we hear most often from organisations considering private 5G deployments.
The first is security. Disaggregate a base station into separate radio, hardware, and software components from different suppliers, connected over open interfaces, and the attack surface grows. Governments have noticed: the UK's telecoms security framework, US NTIA guidance, and similar regimes in Japan and the EU all flag interface security as requiring particular attention in Open RAN deployments.
The second is energy. More components, more boards, more thermal management — potentially more power consumption. Any technology that increases per-site energy draw faces a difficult commercial conversation at a time when operators are under pressure to cut both carbon and electricity costs.
The Secure 5G project, funded under DSIT's Future RAN competition, addressed both simultaneously.
What the Consortium Built
The Compound Semiconductor Applications Catapult provided systems integration and semiconductor fabrication access. Lime Microsystems contributed its software-defined radio platform — a flexible, field-programmable transceiver that has become a reference design for open base station hardware. Arqit brought QuantumCloud, its symmetric key agreement platform using quantum-safe algorithms.
The output is a compact, self-contained "base-station-in-a-box." The RF front-end uses custom GaN-on-SiC power amplifiers designed for high efficiency at the specific operating power levels; the digital baseband runs on Lime's software-defined architecture; and the security layer uses QuantumCloud to establish encryption keys between the base station and the core network, and between the base station and connected devices.
Why Quantum Encryption at the Edge Matters
Classical encryption relies on mathematical problems that are hard for current computers to solve. The concern — and it is one we believe the industry has been too slow to take seriously — is that quantum computers will eventually break widely used public-key algorithms in practical time. The intelligence community calls this "harvest now, decrypt later": adversaries intercept encrypted traffic today, planning to decrypt it once quantum capability matures.
For mobile networks, the risk is concrete. A base station compromised at the key-exchange level exposes every connected device. In critical infrastructure settings — ports, energy installations, defence, emergency services — that exposure is unacceptable. Arqit's approach sidesteps the vulnerability by using a symmetric key agreement protocol that does not depend on computational hardness, extending quantum-safe security all the way to the radio edge. The trade-off is that quantum key distribution adds complexity and cost to the radio unit, and at time of writing, the threat from practical quantum computing remains prospective rather than immediate — but for defence and critical national infrastructure deployments, waiting until the threat is realised is not a viable strategy.
GaN and Efficiency
The power amplifier is the largest energy consumer in a base station. GaN devices offer higher efficiency and power density than silicon LDMOS, but importantly they are not plug-and-play replacements — they must be co-designed with the digital pre-distortion and envelope tracking of the specific baseband platform. The Secure 5G project did exactly that, optimising the GaN amplifiers for Lime's SDR architecture, and the result is a PA stage that turns more input power into useful RF output and less into waste heat.
One Box, Two Answers
The elegance of the prototype is that it answers both objections at once, and we think that matters more than either answer in isolation. An operator evaluating Open RAN no longer needs to accept either a security compromise or an energy penalty. The work Aerix undertook on the ONE WORD project — the GBP 10 million Open Networks Ecosystem Competition effort — demonstrated the deployment realities of open networks in demanding environments. The Secure 5G project now adds a hardware building block that addresses the security and energy layers of that same challenge, in a form factor ready for private networks in defence installations, critical infrastructure, and government facilities. Ultimately, however, prototype validation and production readiness are different things, and we will be watching closely to see how quickly this hardware moves from demonstrator to deployable product.
If you are deploying a private 5G network in a security-sensitive environment and need to understand your options, get in touch. Read more about private network security on our solutions page.